Manhole-cover.



lvm-883,096. -PATENTED MAR. 24, 1908.

` HQ DEL MAR.

MANHOLE COVER.'

APPLICATION FILED JULY 9, 1907.

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UNITED srrirnsgrrnnr omnes.

HARRY DEL MAR, OE NEW YORK, N. Y., ASSIGNOR TO BOILERS AND ENGINEERING COMPANY, OF JERSEY CITY, NEW JERSEY, CORPORATION OF NEW JERSEY.

MANHOLE-COVER.

Specification of Letters Patent.

Patented March 24, 1908.

Application filed July 9, 1907. Serial No. 382,945.

\ ment in Manhole-Covers, of which the following is a full, clear, and exact description.

My invention relates to improvements in manhole plates or covers, such as used in connection with boilers and other receptacles which are subject to internal pressure. As these plates or covers are generally secured, they are subject to this difficulty, that is if, as sometimes happens, the pressure is raised above the usual amount, as for instance in boilers that are being started, and the pressure then drops back to normal, the parts of the manhole will not adjust themselves, and so the boiler will leak around the covering.

The object of my invention is to obviate this difficulty and produce a manhole plate and cover which will be tight under all variations of pressure, and further to make a structure which is simple and inexpensive, and which can be easily applied or removed.

To these ends, my invention consists of a manhole plate or cover, the construction and operation of which will be hereinafter described and the novel features claimed.

Reference is to be had to the accompanying drawing forming a part of this specification, in which similar reference characters indicate corresponding parts in all the views.

Figure 1 is a broken elevation partly in section, of the structure. embodying` my invention, and Fig. 2 is an end view of the boiler, and showing an outside elevation of my improved structure.

The boiler 10 can be of any approved construction, and the part 10 here represents any receptacle which is adapted to be subjected to internal pressure. I have shown it with the usual end part 1l having a manhole therein, closed by the manhole plate or cover 12, which has flanges 13 to fit against the inner wall 1l. I have shown the usual oblong construction so that the cover can be turned around and pulled out when desired, and thrust through the opening when it is to be applied. Extending across the part 12 on the inner side, is a brace 14 which has its end ortions bent inward as shown at 14a, thus caving the middle part opposite and generally parallel with the part I2, but the configuration of the whole top depends altogether upon the shape of the part to which the manhole cover or part I2 is to be applied, and it will be understood, of course, that this brace conforms in a general way to the shape of the wall carrying the said plate l2.

The end portions of the brace are perforated to receive the bolts 15 by which the brace is secured in place, and the middle part is also perforated to receive the bolt 14h, which extends through plate spring llc, and is secured to the plate I2. The end portions of the brace 14 lit against the bushings or collars 16, which also abut with the wall Il, and similar bushings or collars 16L are placed on the outside of the wall, and the bolts I5 extend through these. The bolts are tightened by the nuts 17, and these are covered by the caps 1S which fit on over the nuts and are screwed to the ends ofl the bolts l5, the inner faces of the caps having a ground joint connection with the bushings 16a.

When the manhole plate is applied, the nuts 17 are tightened up, and the brace 14 serves'to hold the manhole plate in position. The spring 14C is adjusted so that it will normally hold the manhole tight, and if there is an excess of pressure, the spring will yield so as to compensate for the said increased pressure, and when the pressure goes back to normal, the spring will assume its normal position, and the manhole plate connections will not be strained, and the cover or plate will be tight'during all the pressure variations.

It will be observed that this apparatus while compensating for pressure changes, can be regulated wholly from the outside, and can be fastened or unfastened from the outside.

I-Iaving thus fully described my invention, I claim as new and desire to secure by Letters Patent l. The combination with a pressure containing receptacle and the manhole plate therefor, of the spring secured to the wall of the receptacle and crossing the manhole, and a plate spring arranged between the brace and the manhole plate.

2. The combination with a pressure-containing receptacle and manhole plate therefor, of a brace crossing the manhole on the inside of the receptacle, fastening bolts extending through the wall of the receptacle and operated from the outside, and a spring arranged between the brace and the manhole plate, so as to bear directly on the latter.

3. The combination with a receptacle and the cover and through the.

the manhole cover therefor, of a cross-brace l the inside of the receptacle, bolts passing 10 on the inside of the receptacle, said erossthrough the Wall of the receptacle, cap nuts brace connecting with the manhole cover, l on the outer ends oi the bolts to make a tight bolts passing through the Wall of the reeepjoint, and a spring carried by the cross-brace tacle and connecting with the cross-brace, and bearing upon the manhole plate.

and caps on the outer ends of the bolts to HARRY DEL MAR. make a tight joint. Witnesses:

4. The combination With a receptacle and H. A. WILSON,

a manhole cover therefor of a cross-brace on l/V. B. HUTGHINSON. 

